The pod of five orcas was spotted in the early hours of Saturday morning 3.6 kilometres (two miles) off the coast of El Hierro, the southernmost of the Canary Islands.
The killer whales – one male, three females and a calf – were photographed and filmed by a group of researchers in Cetaceans and Bioacoustics from the University of La Laguna (ULL), in Tenerife.
The researchers were conducting a project into more little-known whale species when they spotted the black and white orcas, which famously featured in the 1993 film Free Willy.
Killer whales are extremely rare in the waters around the Canary Islands; the species was last seen off the waters of El Hierro in July 2012.
After catching sight of the group of orcas, the researchers followed the mammals for most of the morning, as far as seven miles off the coast of El Hierro according to Spanish daily, 20 minutos.
The Canary Islands are the most biodiverse area in Europe for cetaceans – marine mammals such as whales, dolphins and porpoises – 27 of the more than 80 species registered worldwide have been observed in waters off the Spanish island chain.
Killer whales are among the most famous draw of marine theme parks around the world, such as the SeaWorld chain.
In 2009, a Spanish trainer was killed in Loro Park, Tenerife by a whale that was born at SeaWorld in Orlando, Florida.
The incident was featured in the 2013 documentary about the controversy surrounding captive killer whales, Blackfish.